Gles3
The GLES3 rendering backend. It uses OpenGL ES 3.0 on mobile devices, OpenGL 3.3 on desktop platforms and WebGL 2.0 on the web.
Gles2
The GLES2 rendering backend. It uses OpenGL ES 2.0 on mobile devices, OpenGL 2.1 on desktop platforms and WebGL 1.0 on the web.